It's anyone's guess at this point. This is going to be harder than finding a LD of Grease with digital sound. :/
My curiosity has grown over the 5.1 mixes that some of the SE discs had. The one on the LTK SE trumps the UE.
I'm also puzzled why the early THX mastered Moonraker DVD had a 5.1 track and the later SE disc didn't. My copy is rotted unfortunately, (one of the first DVD's I ever bought) so I'm chasing down a replacement so I can hear that track once again.